Circuit breaker



May 14, 1935. E. zURcHER 2,001,513

CIRCUIT BREAKER Filed June 27, 1933 3 Sheets-Sheet l mm ttovheg Ihvehtor: )fhest Zuvcher,

g His May 14, 1935. E. zURcHER GIRCUIT BREAKER n Filed June 27, 1953 I5 Sheets-Sheet 2 .1:9 mi 'iimlmh 4mm c E WH invento@ ET`heSt Zufche,

May 14, 1935. E. ZURCHER CIRCUIT BREAKER Filed June 27, 1953 Z5 Sheets-Sheet 3 lrwehto Ernest Zuche;

His Att OVheg.

` Patented May 14, 1935 UNITED STATES omcUr'r nimm Ernest Zurcher, Schenectady, N. Y., assigner to i' General Electric Company, a corporation of New York Application June 27, 1933, Serial N0. 677,795`

14 claims.

My invention relates to circuit breakers, more particularly to circuit breakers oi the type provided with arc chutes or housings, and has for an object the provision of a simple, inexpensive and reliable circuit breaker.

While not limited thereto, my invention is particularly applicable to thermally operated switches for the control of electric motors. Heretofore, the arc chutes have been either hingedly connected to the switch base or they have been arranged so that they can be removed as a unit independently of the switch contacts to permit ready inspection of the contacts. In case the contacts have worn considerably and replacement f is to be made it has been necessary to remove the arc chute. Due to carelessness the switch has sometimes been reassembled without placing the arc chutein its proper place and the electric arcs due to the breaking of a heavy current have caused considerable damage to the switch mechanism and have endangered the operators safety.

In carrying out my invention in one form thereof, I provide an arc chute or arc housing which serves not only to enclose the contacts but also as a support for the movable contacts. Consequently, the switch cannot be operated unless the arc chute is in position because the. operating mechanism is connected to it. More specifically, the arc chute or housing is pivotally mounted at one side of the stationary contact and the operating mechanism engages the arc chute on the other side of the stationary contact. In multiple circuit breakers the arc chute is provided with separate compartments ior the respective switch contacts, the walls of the separate compartments cooperating with the base of the switch to enclose at all times the switch contacts forming each pole ,of the'switch. Consequently, a flame-proof structure is provided because the arcs occurring at the contacts are isolated from each other and cannot come into contact with the operating mechanism. An overload device is similarly enclosed to prevent injury to the mechanism in case of extremely high overload current.

For a more complete understanding of my invention, reference should be had to the drawings wherein I have shown in Fig. 1 a sectional elevation of a. switch embodying my invention; Figs. 2 and 3 are fractional sectional elevations showing the operating mechanism vo1' Fig.,1 in different positions; Fig. 4 is a plan view of the switch shown in Fig. 1 with certain parts omitted to show. the construction more clearly; Fig. 5 is an 'elevationot the thermal overload device shown in Fig. 9; Fig. 6 is aplan view of Fig. 5: Fig. 7 is a sectional elevation of a portion of the heating, coil; Fig. 8 is a plan view of Fig. '1;fllg. 9 isa perspective view of the thermal device;Flg. 10 is a perspective view of the heating'element and 5 casing for the thermal device; Fig. 11 is a detailed view of the tripping member; Fig. 12 isa plan view looking into the interior of the arcy chute; Fig. 13 is a. sectional elevation taken on the lines I3-I 3 of Fig. 4, while Fig. 14 is a perspective lview 10 oi' a modiiied form lof arc chute embodying the invention. 'i

Referring to the drawings, I have shown my invention in one form as applied to a triple pole switch provided with a base I0 formed of insu- 15 lating material. The movable contacts II, I2, and I3 and the stationary contacts I5, I5 and I1, Figs. 1 and 13, are identical in construction. Consequently, only one pole of the switch will be described in detail. As shown, the stationary contacts I6, preferably-formed of silver, are secured to the conductors I3 and 20 which are fastened to the base bymeansof screws 2| and 22. 'I'he movable contacts' I2, Fig. y12, are supported by a bridging member provided rwith a rec- 25 tangular opening 2l at its center to receive a rectangular post 3| vfastened to the'arc housing 32 by means of a screw 33. 'Ascrew 3l and a washer 35 serve to maintain the bridging member on the post against the bias of a compression spring 36, the bridging member being thus slidably mounted on the post. f Referring to Figs. land 13, it will be observed that the stationary contacts |6-are mounted upon a ledge or projection formed integrally with the base. Similarly, the stationary `contacts I5 and I'I are mounted upon projections or ledges 4I and 42. 'I'he arcchute orhousingl! formed of insulating material, besides serving-to support e the movable contacts II, I 2'an`d I3 is provided 40 with side walls Il, I5,n and l1 for cooperation with the channels or grooves betweenfprojections 40 to l2, inclusive, ta enclose completely the rcL spective stationary and movable contacts in separate chambers. That is to say, each 'of the walls 45 I4 to 41, inclusive, extends below the upper surfaces of the respective projections 40 to 42, inclusive, when the switch is in either the open or closed position. f f

The movable contact members, secured tothe arc lhousing 32, are simultaneously operatedeto open and closed circuit positionswith a snap action by means of the operating mechanism 50, Figs. l4 inc. The operating mechanism is arranged to rotate the arc housing 32 about a pivot 55 formed by a pair of members 52 and 53 secured to the arc housing by the screws 54 and 55, the member 52 being provided with a pivot pin 56 which extends into a notch 51A provided in the base l0. Similarly, the supporting member 53 is provided with a pivot pin 58 extending into a notch 59. In order to facilitate the assembly of the switch the two supporting members 52 and 53 are connected together by an insulating strip The operating mechanism 50, of any suitable form, is preferably connected tothe arc housing 32 by means of a rod 10 extending into the notches 1| and 1|a provided in the arc housing. The rod 10 is carried at one end of a link 12 which is pivotally mounted on a pivot pin 13 secured to the frame or base 14 of the operating mechanism. In order to impart a snap action to the movable contacts, movement is imparted to the link 12 by a toggle mechanism comprising the links 15 and 16 arranged to be operated to the made and broken positions by means of an over-center spring 18. It will be observed that the over-center spring is connected at one end to a. pivot pin 19 supporting the links 15 and 16, and at its other end to a pin 80 carried by an operating handle 8| provided with a pair of spaced arms secured by a pivot pin 82 to the frame 14. By rotating the operating handle 8| in a clockwise direction from the position shown in Fig. 1 to the position shown in Fig. 2, it will be observed that the spring 80 passes through its dead-center position to apply its bias to the toggle mechanism to operate the links 15 and 16 to the made position. Consequently, the link 12 is operated in a clockwise direction to close quickly the contacts of the switch and of course as soon as the operating handle 8| is returned to the position shown in Fig. 1 the contacts are quickly operated to their open circuit position.

As shown, the operating mechanism 50 includes a current responsive tripping means so that the switch contacts are operated to their open circuit position whenever a predetermined current flows through the switch contacts. The automatic tripping of the circuit breaker is accomplished by the provision of a supporting member or cradle 90, provided with spaced arms disposed on opposite sides of the link 12 but within the legs of the handle 8|, pivotally mounted on a pin 9|. The supporting member 90 has an upturned projection 93 aranged to nest within a notch 94 provided in one end of the link 16. When the switch contacts are in the closed position as shown in Fig. 2, it will be observed that the spring 18 is exerting a force on the toggle mechanism, a component of which is effective to rotate the supporting member 90 in a clockwise direction about its pivot 9|. If this motion is permitted, it will be observed that the notch 94 provided in one end of the toggle mechanism will be rotated beyond the dead-center position, thereby breaking the toggle and causing the switch to be quickly operated to its open circuit position. However, the supporting member 90 is normally maintained in the position shown in Fig. 1 by means of a thermal tripping member |00, Fig. 11, which is secured by a pin |02 to the lower end |03 of the support 00. The tripping member has two outwardly extending latching members and |06 pivotally secured to it by means of a washer |08 and a cotter pin |09 cooperating with the upwardly extending projection ||0. These latching members |05 and |06 are normally biased away from each other by means of a compression spring |I| and into e11- gagement with a pair of gear wheels |I5 and I6, Fig. 4, provided on the thermal overload devices ||9 and |20. Since the thermal devices ||5 and |20 are identical in construction only one of them, the device |20 will be described in detail. As shown in Figs. 9 and 10, the gear wheel ||6 is carried by a sleeve |30 nesting within a metal cylinder |3I. The sleeve |30 is normally soldered to the cylinder |3| and thereby holds the gear ||6 from rotating in accordance with the bias exerted upon it by the tripping member |00. Similarly, the gear I5 is maintained stationary by means of a solder film between its sleeve and cylinder.

As shown in Figs. 8 and 10, the thermal overload device |20 is provided with a heating coil |35 mounted within an insulating casing |36 by,

means of the terminal members |38 and |39. The metal cylinder |3| is supported by a base |40 formed of insulating material and is removable as a unit from the switch base l0. For example, the base |40 of the thermal device is provided with terminal screws |50 and |5| which serve to support conductors |52 and |53, each of which is provided with extensions for completing electrical connections from the conductor |55 to the conductor |56. Similarly, the thermal responsive device ||9 is constructed so that it can be removed as a unit from the switch.

Since the thermal devices are constructed as units the switch can be calibrated for diierent applications by simply assembling the proper thermal device on the circuit breaker for a particular application. Or, if the switch has been assembled with 25 ampere thermal devices it is only necessary to loosen the nuts |60 and |6| and either new heating coils can be assembled on the thermal overload device or by loosening the nuts |63 and |64 new thermal devices can be substituted for the ones already in the switch.

In order to provide a flame-proof construction, it will be observed that the casing |36 is provided with extensions and |1|- arranged to be received in complementary relation with notches |12 and |13 provided in the base |40, the inner walls |12a and |13a of the notches being covered by the extensions. Besides serving to enclose the heating coil, the extensions |10 and |1| protect the heater coil from mechanical injury. For example, if the casing is dropped the extensions will protect the coil from injury.

It will be understood that the switch canebe operated in response to overload in any one of the phases since the thermal devices ||9 and |20 are arranged to be connected respectively on the outside legs of 'a three phase circuit.

In the operation of my switch in response to overload current it will be assumed that the parts are in the positions shown in Figs. 2 and 13 and that an overload current is flowing through the heater coil |35 of the thermal responsive device |20. As soon as the heating coil4 |35 has produced a sufcient degree of heat, the solder securing the sleeve |30 to the housing |3| is melted and the gear Wheel |6 is released for rotation in accordance with the bias applied to it by the latching lmember |05, tripping member |00, supporting member 80 and the over-center spring 18. Consequent to the rotation of the gear wheel ||6 the latching member |05 moves in a direction to rotate the supporting member 90 in a clockwise direction about its pivot 9|. At the same time the tripping member |03 rotated about the pivot pin |80 operates to release the latching member |06 from the gear I5. As soon as the upward projection 93 of the supporting member rotates the notched end 94 of the toggle mechanism over the dead-center position (Fig. 2), the over-center spring 18 breaks the toggle causing the rotation of the link 'I2 about its pivot 13 to operate with a snap action the arc chute 32 to the open circuit position. At the same time the `handle 8| is operated to a mid-position.

In order to reset the thermal responsive devices the latching members |05 and |06 are returned to a position to engage the gears ||5 and ||5 by means of extensions |02 formed integrally with I.the operating handle The extensions |82 shown in section in Fig. 11 engage the pin |02 and act to move bodily the tripping member |00 and the latching members |05 and |06 to their normal latched-in positions when the operating handle is operated from its midposition to the oii position. Since the switch` is reset by the operation of the'handle from the mid-position to the oil position, it will be observed that the circuit breaker is trip free. That is to say, the operating handle 8| even though Operated `cannot maintain the switch in the closed circuit position if a current `exists of sufllcient magnitude to release either of the gears or ||6 because the tripping member |00 must be in its normal position before the switch can be closed and because the tripping of the switch occurs independently of the handle.

In case it is desired to inspect the contacts after a large number of operations, itis only necessary to remove the screws 54 and 55. The supporting members 52 and 53 can be rotated so that the pins 56 and 58- are removed from their notches 51 and 50. The arc chute can then be rotated about the pivot pin until it is freed from the molded base. In case the movable contacts need to be replaced it is only necessary to remove the screws, for example, the screw 34 securing the bridging member 25 of the movable contacts |2 to the rectangular post 3|. Similarly, the stationary contacts can be replaced by removing the screws, for example, the screws 2| and 22 securing them to the base I0.

The arc chute or housing 32 can be constructed in two or more parts if desired. For example, I` have shown in Fig. 14 abase portion |90 and a cover portion |9| arranged to support the movable contacts. In this form of my invention the contacts can be inspected by simply removing a pair of screws (not shown) arranged to extend through the holes |92 and |93 provided in the cover |9| and into the screw threads |04 and |95 provided in the base portion |90.

It will be observed that L-shaped. members IST-|99 are providedv instead of washers to hold the contacts on their respective supporting members. The bent-over portion |99a serves to vary the position of the bridging member. Consequently, the circuit breaker can be assembled so that either the upper or lower` contacts of each bridging member will first interrupt the circuit.

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limitedthereto since many modications may be madef and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

l. A circuit controlling device comprising a base member formed of insulating material and provided with a ledge, a switch contact mounted on said ledge, an arc housing formed of insulating material and provided with walls forming a flame-proof chamber, a second contact mounted within said chamber, means mounting said housing and said base for predetermined relative movement to operate one of said contacts with respect to the other`between open and closed circuit positions, said walls of said housing overlapping said ledge an amount sufcient to provide a flame-proof chamber for both of said contacts when said housing is in either said open or said closed circuit position.

2. A circuit controlling device comprising a base member formed of insulating material and provided with a ledge, a stationary switch contact mounted on said ledge, an arc housing formed of insulating material and provided with walls extending into overlapping relationship with said ledge to enclose said stationary contact, a movable contact secured to said arc housing between said walls for cooperation with said stationary contact to open and close a circuit, operating means connected to said housing for operating said housing and said movable contact between open and closed circuit positions, said walls of said housing overlapping said ledge a predetermined amount when in said open circuit position and a greater amount when in said closed circuit position.

3. A circuit controlling device comprising a plurality of pairs of spaced apart fixed contacts mountedl in alignment, an arc housing formed of insulating imaterial and provided with separate compartments surrounding at all times each pair of said contacts, mounting means providing for relative movement of said housing with respect to said fixed contacts, operating means including a handle, means operable in response to movement of said handle for moving said arc housing between predetermined positions, and a bridging contact mounted in each compartment of saidV arc housing for movement therewith into and out of bridging circuit controlling engagement with the corresponding pair of xed contacts, saidhousing being formed so that each of said compartments surrounds its bridging contact and its cooperating stationary contacts when said housing is moved to either of said positions.

4. A circuit controlling device comprising walls of insulating material forming a flame-proof arcing chamber, a movable contact mounted on one of said Walls of said chamber, means mounting said chamber for a predetermined movement between open and closed circuit positions, a stationary contact, a projection for supporting said stationary contact within said chamber, said -walls of said chamber being formed to overlap said projection when said chamber is in either said open or said closed circuit position.

5. A circuit controlling device comprising a base member formed of insulating material, a stationary contact mounted on said base member, an arc housing formed of insulating materialvand provided with walls surrounding said member, means for detachably mounting said arc housing for movement with respectto said xed contacts, saidhousing being provided with a slot, operating means having an element slidably engaging said slot to eiect movement of said housing between open and closed circuit positions, a switch contact nesting within an adjacent pair of said walls and operable by said housing into and out of engagement with said stationary contact, said walls of said housing surrounding said base member when said housing is in either said open or said closed circuit position.

6. A circuit controlling device comprising a fixed contact, an arc housing for surrounding said contact and provided with a pivotal bearing on one side of the contact and a slot on the opposite side of the contact, means cooperating with said pivotal bearing for mounting the arc housing for movement with respect to the fixed contact, operating means having an element adapted to engage with said slot to effect movementl of the arc housing, and a second contact mounted in the arc chute for movement therewith into and out of circuit controlling engagement with said fixed contact.

'7. A circuit controlling device comprising a base member formed of insulating material, a stationary contact mounted on said base member, an arc housing formed of insulating material and provided with walls surrounding said member, operating means connected to said housing for operating said housing between open and closed circuit positions, a switch contact nesting within an adjacent pair of said walls and operable by said housing into and out of engagement with said stationary contact, said walls of said housing surrounding said member when said housing is in either said open or said closed circuit position.

8. A circuit controlling device comprising a pair of spaced apart iixed contacts, an arc housing provided with walls surrounding said pair of iixed contacts and provided with a support extending between said xed contacts from the opposite wall of said arc housing, means located at one side of said contacts for detachably supporting said arc chute for pivotal movement with respect to said fixed contacts, operating means detachably engaging said arc chute on the opposite side of said contacts and a bridging contact detachably mounted on said support for movement with the arc housing into and out of circuit controlling engagement with said spaced apart fixed contacts.

9. A circuit controlling device comprising a base member formed of insulating material and provided with ledges spaced apart one from the other, a switch contact on each of said ledges, an arc housing formed of insulating material and provided with walls at all times extending between said ledges and overlapping said ledges, and a switch contact secured to said arc housing between each pair of adjacent walls for movement with said arc housing into and out of engagement with said iirst mentioned contact, said walls and said ledges overlapping one another to form flame-proof arcing chambers when said contacts are either in or out of engagement.

10. A circuit controlling device comprising a base member formed of insulating material and provided with ledges laterally spaced apart one from the other, a pair of fixed contacts spaced apart from each other and fastened to each of said ledges, an arc housing formed of insulating material and provided with partitions extending between said ledges and with side walls overlapping said ledges on all four sides thereof to provide flame-proof chambers for each pair of said contacts, a bridging contact mounted on said arc housing between said partitions and said side walls for movement therewith into and out of bridging circuit controlling positions with said iixed contacts, and means for operating said arc housing between said positions.

11. A circuit controlling device comprising a base member formed of insulating material and provided with ledges laterally spaced apart one from the other, a pair of iixed contacts spaced apart from each other and fastened to each of said ledges, an arc housing formed of insulating material and provided with partitions extending between said ledges and with side walls overlapping said ledges on all four sides thereof to provide flame-proof chambers for each pair of said contacts, a bridging contact mounted on said are housing between said partitions and said side walls for movement therewith into and out of bridging circuit controlling positions with said fixed contacts, and operating means for manually operating said are housing between said positions and provided with an overload release for operating said contacts out of said bridging circuit con-4 trolling position, said overload release comprising a solderklm latch, a heating coil connected in circuit with said contacts, and an enclosing casing for removably supporting said coil with respect to said latch.

12. A circuit controlling device comprising a base member formed of insulating material and provided with ledges laterally spaced apart one from the other, a pair of fixed contacts spaced apart from each other and fastened to each of said ledges, an are housing formed of insulating material and provided with partitions extending between said ledges and with side walls overlapping said ledges on all `four sides thereof to provide iiame-proof chambers for each pair of said contacts, a bridging contact mounted on said arc housing between said partitions and said side walls for movement therewith into and out of bridging circuit controlling positions with said fixed contacts, operating means for operating said arc housing between said positions, and a thermal overload device for said operating means comprising a solder nlm latch, an insulating support for said latch, fastening means for securing said support to said base member, said support being provided with notches on its opposite walls, a heater coil for said latch, an enclosing casing for said coil provided with projections for protecting said coil from injury and for cooperation with said notches thereby to enclose said heating coil.

13. The combination with a circuit controlling device provided with contacts operable between open and closed circuit positions, of a thermal overload device for operating said contacts from a closed circuit position to an open circuit position comprising a solder film latch, a support formed of insulating material for said latch and provided with notches on opposite sides of said latch, a heating coil for said latch and an enclosing casing for said coil provided with extensions arranged to rit into said notches.

14. An overload device comprising a support of insulating material, a member rigidly secured to said support, a second member normally fastened to said iirst member by a solder film, a heater coil for said members, said support being provided with notches on the outer portion thereof, and an enclosing casing for supporting said coil and provided with extensions arranged to fit into said notchesv so as to form in cooperation with said baseA a flame-proof chamber for saidcoil.

ERNEST ZURCHER. 

